Hot Rods Cowl Steering . . . just stop !

I have to admit that after reading this thread it has forced me to change my plans regarding the drag link on my replica champ car under construction. I started out with one long drag link from the cowl steered pitman arm all the way to the front spindle. Now I am adding an intermediate link to bring the length of the second shorter length in line with a more optimum bump steer situation. This is similar to how Logghe Stamping Co. did my cowl steered altered drag roadster and I see why.

 

So, in y'alls expert opinions, how much suspension is a race car s'pose to have ? My vintage race car has the rear leaf springs bolted together. Applying physics & geometry to that, it seems it has zero travel. Rigid in fact....

 

So gimp, you think I should street rod my vintage race car then....? I think that's against the rules on this site....

 

The harder one tries to violate a Law of Physics, the higher the probably of death rises.

Getting away with something doesn't make it safe, or sound.

That's Russian Roulette Logic©.

You can chamber one round in in your revolver. Every day you can spin that chamber and then pull the trigger, and live to die of organ failure at 105.

That doesn't mean Russian Roulette is safe.

It means you are damned lucky.

 

People saying stuff but not saying anything.

It’s like using the term “properly welded” which to me is bullshit. Because there’s so much information and so many variables under those two words. I get it, you’d have to write a very thick book encompassing all things to reach what “properly welded” actually covers and since few read those already published they won’t read what’s personalized for them either.

The animations posted earlier clearly show the problem when changing a rectangle to a parallelogram via suspension travel. The potential for problems is inherently built in and severity of the problem varies with the amount of movement. In simple terms, in the unlikely scenario of Zero suspension travel there is Zero problem. Any amount of suspension travel beyond Zero causes problems in proportionate size to the amount of movement.

 

I'm a converter. I initially built my RPU with cowl steering. Partially due to stubbornness and I like finding stuff out for myself. Although it was manageable and I drove it for a season with it, when I was given an f1 box I switched it out just to see how much better it would handle. I'm pleased with the outcome.

 

I’m looking at getting a steering shaft around a big ass 392 hemi now,,, since my original plan was cowl steering.
It’s doable but gives me one or more of the following-Column angle I hate, a wheel position I don’t like, in the foot well.
I can get around it with a steer clear I don’t want, or a Vdog that’s stupid money.
That leaves a a pair of rodeo units or
A few more parts into the cowl steering.

It’s been asked a few times already and nobody seems to comment on the set up.

 

"My vintage race car has the rear leaf springs bolted together. Applying physics & geometry to that, it seems it has zero travel."

Is it a rear-steer? Must be a handful.

 

Its not clear to me why the end of that drag link wasn't put right by the pivot point for the radius rod or hairpin

 

Post a pic of left side of your car centering on rad rod pivot.

 

I’m not there yet

 

Is it what's pictured you're asking for a comment on? That picture looks like one afterthought applied to another. Maybe because it's all outside, maybe because it almost looks like it "wants to be something" but is really evils we can't discern which is the lesser of? Chains and sprokets work no matter who builds it. Safe? I've seen a piece of heavy equipment with it where lives are at stake (although I don't recall what it was). I'm a fan 'Vic, what I see will work, but sadly can not be unseen.

 

Spent all morning reading this thread. Good info to be had. Thanks Mr. Eastwood for your contribution. I think overall it has many on here rethinking the way to do something safer and sound and that is a good thing for all of us on the road.

 

The micro details don’t mean too much it’s the macro design of the intermediate bell crank and vertical drag link. A guy could have the vertical rod inside the kick panel almost easier.

it would be relatively simple to tuck a steer clear type unit into the kick panel and run a low pitman arm with a cowl steering box. But The damn things don’t have a pitman arm spline and they are supposed to go between the steering wheel and the steering box, not between the box and pitman arm. Seems it would need to be 20 times stronger on that side of the box.

 

I've read this thread entirely thanks to Dana Barlow, regarding some questions and issues i had concerning the installation of a Schroeder box in my 32 and i must say i've learned a lot... so in this time of epidemic confusion, it's not a wasted day. Thanks Dana and many others but especially mr Eastwood for starting this topic years ago. that made me thinking of what i'm really looking for and the proper and safest way to go there, be it with a Schroeder box, put back my Vega box or maybe go with a Neal Jennings renewed box to get a more vintage, authentic 50's era look.
Be safe. Cheers.

 

I can't think of a single form of motorsport in which more travel isn't better (or wouldn't be but for other considerations.)

 

I like that idea. Inside the kick panel you've got length and height but not so much width, so there is the opportunity to use bigger sprockets to reduce the tension in the chain. Use a serious motorcycle chain: those things are strong, and in that position would have a cushier life than on a motorcycle. No need for complete enclosure either. The trim panel should keep it out of trouble, even if it also keeps it out of mind so that you'd forget to lubricate it.

Though come to think of it, strictly the chain is redundant as it'd never need to do a complete revolution, so simplifying it brings you back to the vertical link in the pic.

I can't remember if I mentioned it before: another way would be to rotate the steering box so the output shaft points down, I'm guessing about 30° from the horizontal, depending on the amount of space there is above or ahead of your left foot. The pitman arm would then be slightly Z-shaped and perhaps 15% longer, so the perpendicular distance to the output shaft is maintained and the main, middle part of the arm sits vertical at straight-ahead.

 

If I only have 1/2'' of travel, what tyre pressure do I run?

 

7

 

Yeah it's rear steer when the front wheels are up....1964 C/gas champion

 

funny!
I get that.

 

Funny, but also true.....

 

Just got an alert to a comment on this thread. It's been 3-4 years since I was reprimanded for my cowl steering ignorance. Well it's been over 35K miles and I'm still lookin for bump steer.

 

OK, STOP WORRYING, NOW !!!! STOP I

 

Looks like good geometry to me. The pitman shaft is close to the pivot point of the hairpin, from a for and aft perspective. And close to parallel with it. Good job!

 

Those headers look interesting too.

 

Great thread. Now for some comic relief by telling on myself a bit. About 8 years ago I built a '31 Model "A" Chopped Sedan, highboy style. I wanted something different so I found an old sprint car cowl steering box and fabricated it all in place near the end of the build. It was a power unit and I had a power steering pump etc. so I hooked them up.

We were in the final stages of the build and I am measuring for the steering rod with a wooden dowl. I hated it. Aesthetically speaking, to me it just looked stupid. From the pitman arm that came with box it was sort of a steep down hill angle and just didn't look right. I felt like it would look better if it was more parallel with the chassis. But there was no way to get the box any lower in the car. The only answer I could see was a longer pitman arm...LOL

I hit Speedway Motors and in the Srintcar section they had them. I had already took the measurements and I figured at the time if they made one 18 to 21 inches long that would be in the ball part...they did! So I ordered it along with a correct length steering rod and away we went. Well a week or so later we are ready for the first drive. We pushed it out of the shop behind my house and aimed it down a long driveway. I fired it up and decided to do a little burnout to introduce her to the world. I power braked it for just a few seconds and lit the hides. She is starting to slowly kick her backside out a bit and I have turned the steering wheel a bit to adjust for it.

I let off the break, she bites hard and we are off. But unbeknownst to me, the front wheels are turned complete hard to the right and when she bites we take a right turn like we are on rails straight for the shop. I quickly try to straighten it up but that movement locks the front wheels all the way to the left and the car has to react so quickly that it felt like it was going to flip over. I am nearly tossed to the passenger seat but I am stilling trying to drive it. Back to the right and I slam back into the driver's side door panel and I nearly hit the house, then the neighbors the tree, then my house then my neighbors shrubs, then my house, then my my neighbors front yard, then my yard and finally skid it to a stop in the grass. It seemed to all happen in slow motion but it was just a few seconds.

My Dad who has been watching in horror comes running up and says what in the world was that? He said it has a death wobble. I said we were not going fast enough for that but it was one death defying ride I will assure you! We pushed it back out of the yard and onto the driveway again. I fired it up and as it sat there in park I turned the steering the wheel. It only took about two inches of steering wheel travel in either direction to go lock to lock. It was the craziest thing I have ever witnessed. Being a powered system didn't help either. You could literally just wiggle the steering wheel back and forth and the front end reacted so quickly that it would bounce the front of the car!

Now people in the know had warned me that sprint car boxes were a bit faster ratio than standard automobile steering units. But that was rediculous. The maker of the vintage box was still around so I called them the next day to see if maybe there was a way to gear this thing down etc. I am talking with a tech guy that says there is no way to change the ratio (at least not in the box itself). He says he is surprised because in the world of sprint car boxes theirs are actually the closest to standard steering there is. He said it might be 10 percent quicker at the most. He then says what is the length of the pitman arm. I said 20 inches. He exclaimed, "Good Lord man that is undriveable!"

Tell me something I don't already know. LMAO. After taking his advice on the correct length it handled very nicely!

 

Comic relief from a man not ashamed to talk about his screw ups. It’s only Sunday morning but I think this could be the post of the week, thanks for the laugh.

 

Ditto!
We gotta remember that this Hot Rod stuff is not all that important in the overall scheme of things. I assume my screw-ups are typical for a hobbyist's and I take some comfort in that. That's what makes the successes so sweet.

 

it’s not, being parallel has nothing to do with the pivot points , I think if you go back to the first couple of pages there was a couple operational models as examples of what goes on